Propellant configurations for use in firearms



H. E. MICHAEL 3,264,997 PROPELLANT CONFIGURATIONS FOR USE IN FIREARMSAug. 9, 1966 Filed July 20, 1964 FEG.!.

H E WVENTOR. AROLD ICHAEL WW ATTORNEY United States atet ice

3,264,997 PROPELLANT CONFIGURATIONS FOR USE IN FIREARMS Harold E.Michael, 30714 Tarapaca Road, San Pedro, Calif. Filed July 20, 1964,Ser. No. 383,759 1 Claim. (Cl. 102-98) This invention relates topropellants as used in firearms such as revolvers, pistols, rifles,machine guns, and artillery.

Presently available firearm propellants are in the form of smallparticles of charge, each particle being in the form of a tubularsection of relatively thick wall and of a length corresponding toapproximately two to three times the diameter of the section. Theconfiguration is designed to the provide a nearly constant burning areafor each particle until the propellant particles are entirely consumed.For a given propellant composition and burning rate, the burning time isdetermined by the thickness of the tubular wall section of thepropellant particles. The burning time is selected to obtain the maximumprojectile velocity for the condition of projectile weight, bore andbarrel length of the firearm, and propellant energy.

When propellant particles or grains of the foregoing configuration areloaded into a typical cartridge case, the volume occupied may containsixty percent propellant and forty percent voids. As a consequence ofthis relatively low density of actual propellant in the cartridge, onlya given energy can be packaged in a given sized cartridge.

With the foregoing in mind, it is accordingly a primary object of thisinvention to provide novel propellant configuration which result in anincrease in the density of the propellant thereby enabling the size ofthe cartridge case required for a given weight of propellant to bedecreased. As a consequence, certain economies in size and weight of thecartridge case and of cooperating equipment relating to the cartridgecase can be effected.

Brieflly, this and other objects and advantages of this invention areattained by avoiding the use of hundreds of small particles or grainsand instead providing the propellant charge initially as an integralsolid mass in the shape of an enlarged cylinder which corresponds to thereceiving portion of the shell so that if the charge were placed in theshell, there would be substantially no voids and thus one hundredpercent filling of the shell by the propellant. However, without furthermodification, there would not be provided the necessary exposed surfacesto effect controlled burning of the propellant. Accordingly, and inaccordance with various species of the present invention, thecylindrical charge portion after being shaped to be received within theinterior receiving portion of the shell is cut in a manner to enable atleast partial separation of the cylindrical shaped charge into smallportions to take place thereby providing an increased burning area. Inaddition, the cylindrical shaped charge may be provided with at leastone axial bore of small diameter running from one end of the cylindricalshape to the other to provide further burning area.

By means of the foregoing cuts and bore, the amount of voids may bereduced to 1cm than five percent of the volume occupied by thepropellant without sacrificing the desired burning rates.

A better understanding of the invention will be had by referring toseveral embodiments thereof as illustrated in the accompanying drawings,in which:

FIGURE 1 illustrates an exploded view of a shell and chargeconfiguration in accordance with one embodiment of this invention;

FIGURE 2 is a cross-section of the charge illustrated in FIGURE 1looking in the direction of the arrows 22;

FIGURE 3 illustrates in partially exploded view an other embodiement ofcharge configuration in accordance with this invention;

FIGURE 4 is a cross view taken in the direction of the arrows 4-4 ofFIGURE 3;

FIGURE 5 illustrates yet another charge configuration in accordance withthis invention; and

FIGURE 6 is a cross-section looking in the direction of the arrows 6-6of FIGURE 5.

Referring first to FIGURE 1, there is shown a firearm shell 10 ofcylindrical configuration. Cooperating with this shell is acylindrically shaped bulk charge 11 having a diameter and lengthcorresponding to the interior receiving dimensions of the shell 10.

In accordance with the first embodiment of the invention illustrated inFIGURE 1, the cylindrical charge 11 is provided with a series of cutsextending generally normally to the axis of the cylindrical shapedcharge to separate the charge into a plurality of discs such asindicated at 12. Also provided is a central bore 13 extending axiallythrough the cylindrical configuration. By this arrangement, thereresults a series of stacked discs of propellant whose thickness isselected to permit the propellant to be consumed within the timerequired to produce the maximum energy to be tranferred to theprojectile. Since each disc is provided with a hole as a consequence ofthe bore 13, there is defined an ignition passageway through thecylindrical shape when the primer is fired. As the combustion processprogresses from the cylindrical surface of the ignition passageway inthe form of the bore to the plane surfaces of each disc, the resultinggas pressure forces the discs to separate and thereby become distributedalong the bore of the firearm as the propellant discs are consumed.Typically, the bore 13 may be about onefifth of the overall diameter insize and the discs may be of the order of .010 inch in thickness forhand held firearms.

In the cross-section view of FIGURE 2, the actual size of the bore 13 isgreatly exaggerated for purposes of clarity.

FIGURE 3 illustrates another configuration in which a cylindrical charge14 is provided with a spiral cut 15 extending generally towards the axisto define a general helical configuration for the charge as indicated inthe exploded portion at 16. A bore 17 is provided as shown. This mannerof cutting the charge provides the required burning surface area withoutincreasing appreciably the volume percent of voids.

FIGURE 4 illustrates the appearance of the helical configuration whenlooking in the direction of the arrows 44 of FIGURE 3. Again, thecentral bore 17 provided in the charge has been exaggerated in size forpurposes of clarity.

FIGURES 5 and 6 show yet a third embodiment of the invention whereinthere is provided a cylindrical charge 18 having a plurality of cuts 19and -20 extending in from diametrically opposite sides to define partialdiscs 21 which have their opposite diametrical ends alternatelyconnected together. The cuts in every instance intersects a central bore22 so that there is communication between the various burning surfaces.

In the embodiments of FIGURES 36, the axial distance between the variouscuts would be of the order of .001 to .01 inch for hand held firearmsand larger for field shells.

In the cross-section of FIGURE 6, there is shown a burning depressantcoating 23 applied to the exterior burning surface of the cylindricalcharge 18. Such a burning depressant may be desirable to provide furthercontrol over the burning rate and could of course be applied to 3 any ofthe embodiments of FIGURES 14 and on any of the exposed surfaces, eitherwithin the internal bore and/ or on the sidewalls defined by the cuts.

It is important in the various configurations described that theseparated or partially connected disc-like sections resulting be easilyseparable in order to avoid errosive burning which would take place ifthe propellant surfaces could not separate easily.

Since the density of propellant within the shell has been greatlyincreased by the configurations described in FIG- URES 1-6, it is veryimportant that the initial burning rate be held low compared to presentpractice in order that the bullet may be started down the barrel thuscreating a gas expansion space for the more rapid burning that is tofollow. This initial low burning rate is necessary in order to preventthe gas pressure from developing to such a high level that the resultantincreased rate of combustion will generate gas at a faster rate than becan accommodated by the space behind the advancing bullet. Thiscondition compounds itself and may result in damage or destruction ofthe gun breach.

This control of the burning, as stated, may be effected by the use of aburning depressant such as indicated at 23 in FIGURE 6. This burningdepressant will hold the burning rate at a low value when first ignitedbut is removed as the burning progresses until the final burning istotally completed.

Also, the depressant may be applied only to the outer cylindricalsurface of the various configurations illustrated in the drawings sothat active burning initiates at the inner bore surfaces of the smallbore passing axially through the cylindrical shape. As the burningprogresses from the inside towards the exterior, the surface exposed tothe flame is increased so that the desired increased rate of burning isautomatically effected.

While only three basic configurations have been described in detail inthe drawings, it should be understood that various furtherconfigurations may be effected without departing from the scope andspirit of this invention. The essential feature is that of providing aneffectively solid cylinder of propellant which contains enough surfacearea to insure its complete burning within the required time and whichdistributes itself evenly along the bore while burning. Accordingly, theinvention is not to be thought of as being restricted to the particularembodiments set forth merely for illustrative purposes.

What is claimed is:

A propellant configuration for use in a cylindrical firearm shell,comprising: a cylindrically shaped charge including an axially directedlbore extending therethrough, said charge having a plurality of lateralcuts extending generally normal to the longitudinal axis of said chargeto intersect said bore at substantially right angles, said cutsinitiated from opposite sides of said cylindrical charge in an alternatemanner and extending completely through said bore and the major portionof the grain diameter to define closely adjacent disc portionsalternately connected at their diametrically opposite ends, whereby saiddisc portions are at least partially separable to progressively increasethe exposed burning area as the charge is progressively burned.

References Cited by the Examiner UNITED STATES PATENTS 660,567 10/1900Gathmann 10298 660,568 10/1900 Gathmann 10298 716,768 12/1902 Scott102-98 1,274,791 7/1918 Gerdom 10298 2,529,791 11/1950 Whitworth et a1102--39 2,712,283 7/1955 Golden 10298 X 2,933,041 4/1960 Ambrose 102-983,048,112 8/1962 Shope 10298 BENJAMIN A. BORCHELT, Printary Examiner.

R. F. STAHL, Assistant Examiner.

